This invention relates to an improvement of a retractor device for reeling seat belts for protecting a passenger in a vehicle.
A conventional retractor for a seat belt mechanism mounted in a vehicle is designed to sense an acceleration of a vehicle body or an acceleration of the belt to be drawn by movement of the passenger upon emergency of the vehicle and to stop rotation of a reel shaft for reeling the seat belt. However, in such a retractor, even when the rotation of the reel shaft is prevented, the belt is additionally drawn out from the retractor due to tightening of the belt wound on the reel shaft by an inertia of the passenger moving forwardly. As a result, restraining of the passenger by the seat belt is insufficient so that the passenger may hit against a steering wheel or an instrument panel in front of the passenger and be injured.
Also, in a passive seat belt mechanism in which one end of the seat belt is supported by a door of the vehicle and the belt is automatically set into a restraining position and a releasing position with respect to the passenger depending on closing and opening of the door, the belt is reeled into the retractor by a substantial amount in said restraining position so as to permit the belt to be switched from the restraining position to the releasing position. This results in an increase of drawing of the seat belt due to said tightening of the belt wound on the reel shaft, so that restraining of the passenger by the seat belt becomes more insufficient.